Valve

ABSTRACT

The invention relates to a valve ( 21 ) for a fluid or gaseous medium, with a displaceable valve body ( 8 ), by means of which the clear flow cross-section is adjustable. The valve ( 21 ), viewed in the direction of flow, comprises a pressure sensor ( 1 ) up- or down-stream of the valve body ( 8 ), to record the pressure of the medium and the valve body ( 8 ) is controlled depending on a signal from the pressure sensor ( 1 ) and/or an external controller ( 2 ).

The invention concerns a valve for a liquid or gaseous medium comprisinga movable valve body, by way of which the internal through-flowcross-section is adjustable.

Valves of that kind are known and are used in many sectors in the watereconomy or industry, in which water or other liquid media, possibly alsogaseous media, have to be precisely controlled, metered and distributed.The known pressure regulators are designed in such a way that they keepthe pressure constant over a predefined volume flow. Under the conditionthat there is an adequate volume flow, this means that adownstream-disposed nozzle is acted upon by the required (calculated)pressure. In practice however both parameters consisting of pressureflow and volume flow are found to be variable.

Therefore the object of the invention is to provide a valve which, evenwith a variable volume flow, can act on a downstream-disposed nozzlewith a constant or a defined variable pressure.

According to the invention that is achieved in that—viewed in thethrough-flow direction—the valve has upstream and/or downstream of thevalve body a pressure sensor for detecting the pressure of the mediumand the valve body is regulated in dependence on the signal from thepressure sensor and/or an external control unit, in which respect it hasproven to be particularly advantageous if the regulating device isarranged directly at the valve, for example in the form of an electroniccircuit on a circuit board.

The fact that the valve has its own regulating circuit makes it possibleto provide for controlled variable pressure regulation. This means thatthe amount of water issuing from the nozzle disposed downstream of thevalve no longer has to be determined, as hitherto, by way of replacingnozzles with different nozzle diameters, but on the contrary it issimply regulated with the pressure in the case of a given nozzle. If, asin accordance with a further embodiment of the invention, the regulatingdevice is adapted for stepless regulation of the pressure and/or forswitching the valve on/off, a valve of that kind embodies two componentsin one construction, namely a pressure regulator and an on/off valve.

A particularly advantageous embodiment involves a valve having a valvehousing in which are arranged a flexible hose and as the valve body apinch device for continuously throttling the through-flow of the flowmedium, wherein a pressure sensor is arranged upstream and/or downstreamof the pinch location and the pinch device is regulated in dependence onthe signal from the pressure sensor and/or an external control unit.

In order not to falsify pressure values, a further embodiment canprovide that the wall thickness of the hose is reduced to a minimum inthe contact region with the pressure sensor arranged outside the hose.For that purpose it has proven to be particularly advantageous if thevalve housing has at least two central guides which are orientedsubstantially transversely with respect to the longitudinal direction ofthe hose and in which the pressure sensor and parts of the pinch deviceare arranged so that, besides a simple structure, this additionallyaffords protection for the delicate pressure sensor.

In accordance with a further aspect of the invention the pinch devicecan be hydraulically actuable, thereby providing for particularly exactadjustment of the reference pressure. In order however to keep thestructure as simple and maintenance-free as possible, a furtherembodiment of the invention can provide that the pinch device iselectrically actuable. In that case it has been found to be particularlydesirable if the pinch device includes at least one slider, a lever anda motor, preferably a servomotor, wherein the motor drives the lever andthe lever actuates the slider which presses shut or opens the hosethrough-flow passage. Electrical actuation of the slider by way of aservomotor provides an environmentally friendly and approximatelymaintenance-free structure.

In accordance with a further aspect of the invention it can be providedthat the valve body is adapted to be actuable by a piston which can beacted upon at both sides, wherein the piston is arranged in a pistonhousing and at least one chamber can be acted upon with a variablepressure by way of a control valve. A technically simple structure isafforded if the control valve is driven by a linear drive, for example aservomotor or voice coil motor, the linear drive being regulated independence on the signal from the pressure sensor. In that respect ithas been found particularly advantageous if the control valve is in theform of a conical needle and is arranged in a communicating passage, byway of which the regulating medium is fed to the chamber.

The invention further seeks to provide an apparatus for the dischargeover a large area of liquid media, in particular water, comprising acentral liquid source, a liquid conduit system, a central control unitand electrical control lines to individual valves at a plurality ofdistributed discharge locations of the liquid conduit system.

Preferably the valve according to the invention is used in relation to asprinkler or watering system in order to achieve precise controlleddistribution of water. With precision watering of that nature parametersmeasured for example by moisture or temperature sensors and/or satellitemonitoring are analysed by the system and the necessary delivery ofwater is accordingly regulated differently with pinpoint accuracy andthus valuable water is saved. In addition a watering system equippedwith such regulating valves according to the invention permits both thelinear operation and also circular operation with the same nozzleequipment.

In order to be able to specifically switch individual nozzles on or off,in accordance with a further alternative configuration of the apparatusaccording to the invention it can be provided that at least a part ofthe valves can be individually continuously adjusted in respect ofthrough-flow quantity and/or switched on/off, so that no additionalvalves with expensive and complicated solenoid control have to befitted.

Further advantages and features of the invention are described ingreater detail hereinafter with reference to the specific description.In the drawings:

FIG. 1 is a diagrammatic view in section through a valve according tothe invention,

FIG. 2 is a diagrammatic representation of a regulating circuit,

FIG. 3 is a diagrammatic view of an apparatus for the discharge over alarge area of liquid media, and

FIG. 4 shows a diagrammatic view of a further embodiment.

The valve 21 shown in FIG. 1 comprises a profiled rubber hose 5 which inprinciple is flat and which is shaped round towards the ends, for thesake of simplicity of manufacture. The hose 5 is embedded in a valvehousing 4 which has two guides 6 which afford access to the hose 5.Fitted in the upper guide 6 is a slider 8 which is displaced by way of alever 9 which is driven by a servomotor 10 or voice coil motor andpresses the hose 5 shut (broken line) or opens it. The lower guide 6serves as a seat for the pressure sensor 1. In the contact region 7 withthe pressure sensor 1 the wall thickness of the hose 5 is reduced to theminimum. The regulating device 3 is mounted in the form of an electroniccircuit on a circuit board to the housing 4 of the valve 21. The valvehousing 4 is closed upwardly and downwardly by connecting sleeves 12,12′ so that the pressure regulating valve 21 is ready to be installed.The upper sleeve 12 has a feed flow opening 13 through which the mediumto be regulated is introduced, A nozzle 15 with a nozzle opening 16 isarranged downstream of the valve 21, connected to the lower sleeve 12′.

In the valve illustrated in FIG. 1 the valve body substantiallycomprises the slider 8 and the hose portion which is pressed in by theslider, Alternatively it would be possible to use the slider directly asthe valve body, without a hose, in which case then suitable seals arerequired.

The mode of operation of the valve 21 according to the invention isdescribed in greater detail hereinafter by means of the regulatingdevice 3 shown in FIG. 2, The regulating device 3 has a storage means 17and a regulator 18. The storage means 17 receives a through-flow amountin l/min by way of an external control unit 2 or from the user, andstores the resulting system pressure and the nozzle size. From thosevalues, it calculates the P_(ref) which it passes to the regulator 18.The pressure sensor 1 which is fitted in the valve 21 detects theP_(act) and passes the value to the regulator 18 of the regulatingdevice 3. In dependence thereon the motor 10 is operated, which in turnactuates the slider which compresses the hose 5 to such an extent untilthe required pressure P_(ref) is set.

In the case of the apparatus shown in FIG. 3 the valves 21 are connectedby way of a liquid conduit system 20 to a central liquid source 19. Allpressure regulating valves 21 are also connected by control lines 22 toan external control unit 2. In addition the valves 21 can be connectedby a detection line which makes it possible to simply replace valves 21in the case of a defect without losing the coding.

In the valve shown in FIG. 4 the flow medium passes through the intake Ainto the valve. The fluid flows around the piston housing 109, and inthat situation water flows through the opening 112, the gap between thepin 108 and the valve body 109, into the chamber 113 and acts on the topside 111 of the piston 101. A force is produced downwardly, in thedirection of flow. The purpose of the pin 108 is to keep the fine gap112 free of deposits and sediment, with its movements. At the same timethe medium flows through the lower openings 103 into the chamber 114 andacts on the underside 110 of the piston 101. An upward force isproduced. The two chambers 113 and 114 are separated by a sealingelement 102, preferably by a diaphragm, in order to keep the pressuresin the chambers 113 and 114 separate from each other. The piston 101 canmove axially up and down. Disposed at the lower end is a thrust rod 115which, in dependence on the position of the piston 101, entirely opensor closes the opening 116 and in that respect produces a pressure drop,depending on the respective position of the piston 101.

The pressure sensor 1 which is separated from the water by a thin rubberdiaphragm 7 measures the pressure present and passes the actual value tothe regulating device 3 where it is compared to the reference value. Theregulating device 3 subsequently passes a signal to the linear drive 10by way of the control line 24. That linear drive 10 can be a servomotoror a voice coil motor. A needle 104 which tapers towards the end ismoved axially in relation to the communicating passage 105 by the lineardrive 10. The communicating passage 105 communicates the pressurechamber 113 with the passage 107 which returns the regulating mediumagain. The needle 104 is sealed by sealing elements 106, preferably adiaphragm.

The valve is regulated by way of the differential pressure which isproduced between the gap 112 and the communicating opening 105 which isconstricted by the needle. In that case the pressure in the two chambers113 and 114 is set such that the piston 101 comes to a halt in a givenposition. In that case the thrust rod 115 is so positioned with respectto the opening 116 that the reference pressure value is achieved. Whenthe needle 104 closes the communicating opening 105 the force producedby the piston face 111 is greater than the force produced by the pistonface 114, and the valve is entirely open. That is the case as long asthe intake pressure at A is lower than the desired reference pressure.If the needle 104 is entirely arrested and the communicating opening 105is entirely free, the force produced by the piston face 114predominates. The piston 101 is displaced upwardly, in that case thethrust rod 115 closes the opening 116 and the valve is shut.

Each position of the needle 104 which does not entirely close orentirely open the communicating opening 105 produces a pressuredifference which moves the piston 101 into a given position. In a mannercorresponding thereto the opening 116 which is opened by the thrust rodproduces the desired pressure drop to achieve the reference pressurevalue which is required to produce a given volume flow through the fixednozzle 15.

It will be self-evident that the invention is not limited to thesespecific embodiments by way of example. On the contrary all materialsand alternative configurations which are suitable for carrying theconcept of the invention into effect can be used.

1. A valve for a liquid or gaseous medium comprising a movable valvebody, by way of which the internal through-flow cross-section isadjustable, wherein the valve has a pressure sensor for detecting thepressure P_((act)) of the medium, wherein the detected pressureP_((act)) is passed from the pressure sensor in the form of electricalsignals and is supplied to a regulating device whose regulator operatesthe valve body in dependence on the signal from the pressure sensor,wherein the regulating device ascertains a pressure reference valueP_((ref)) which it presets for its regulator, wherein viewed in thethrough-flow direction, the pressure sensor is arranged downstream ofthe valve body and the stem of the valve body is operatively connectedat the drive side to a pressure chamber, wherein the pressure chamber isconnected by way of a conduit or a through-flow opening to theintake-side volume flow of the liquid or gaseous medium and is actedupon thereby with pressure.
 2. A valve as set forth in claim 1, whereina nozzle with a fixed nozzle opening is arranged at the discharge sideof the valve on the valve housing.
 3. A valve as set forth in claim 1,wherein the regulating device ascertains the pressure reference valueP_((ref)) in dependence on the reference through-flow amount(l/min_(ref)) with inclusion of the nozzle opening of thedownstream-disposed nozzle.
 4. A valve as set forth in claim 1, whereinthe regulating device is adapted for stepless regulating of the pressureP_((act)).
 5. A valve as set forth in claim 1, wherein the regulatingdevice is adapted for switching the valve on/off.
 6. A valve as setforth in claim 1, wherein the regulating device is adapted for switchingthe valve on/off and for stepless regulating of the pressure P_((act)).7. An apparatus for the discharge over a large area of liquid mediacomprising a central liquid source, a liquid conduit system, a centralcontrol unit and electrical control lines to individual valves at aplurality of distributed discharge locations of the liquid conduitsystem, wherein each of the individual valves comprises a valve as setforth in claim
 1. 8. A valve as set forth in claim 1, wherein a nozzleis provided in a releasable nozzle body.
 9. A valve as set forth inclaim 8, wherein the nozzle is provided in a screwable nozzle body. 10.A valve as set forth in claim 1, wherein the regulating device isarranged directly at the valve housing.
 11. A valve as set forth ifclaim 10, wherein the regulating device is in the form of an electroniccircuit on a circuit board.
 12. A valve as set forth in claim 1, whereinthe valve body is adapted to be actuable by a piston which can be actedupon at both sides, wherein the piston is arranged in a piston housingand at least one chamber can be acted upon by way of a control valvewith a variable pressure.
 13. A valve as set forth in claim 12, whereinthe control valve is in the form of a conical needle and is arranged ina communicating passage, by way of which the regulating medium is fed tothe chamber.
 14. A valve as set forth in claim 12, wherein arranged inthe piston housing for each chamber is at (east one through opening forthe liquid or gaseous medium.
 15. A valve as set forth in claim 1,including a valve housing in which are arranged a flexible hose and apinch device as the valve body for continuously throttling thethrough-flow of the flow medium, and wherein arranged downstream of thepinch location is the pressure sensor which transmits the detectedpressure P_((act)) in the form of electrical signals and the pinchdevice is regulated in dependence on the signal from the pressuresensor, wherein the regulating device presets the pressure referencevalue P_((ref)).
 16. A valve as set forth in claim 15, wherein the valvehousing has at least two central guides which are oriented substantiallytransversely with respect to the longitudinal direction of the hose andin which the pressure sensor and parts of the pinch device are arranged.17. valve as set forth in claim 15, wherein the wail thickness of thehose is reduced in the contact region with the pressure sensor arrangedoutside the hose.
 18. A valve as set forth in claim 15, wherein thepinch device is hydraulically and electrically actuable.
 19. A valve asset forth in claim 15, wherein the pinch device is hydraulicallyactuable.
 20. A valve as set forth in claim 19, wherein the pinch deviceincludes at least one slider, a lever and a motor, wherein the motordrives the lever and the lever actuates the slider which presses shut oropens the hose through-flow.
 21. A valve as set forth in claim 20,wherein the motor is a servomotor.
 22. A valve as set forth in claim 15,wherein the pinch device is electrically actuable.
 23. A valve as setforth in claim 22, wherein the pinch device includes at least oneslider, a lever and a motor, wherein the motor drives the lever and thelever actuates the slider which presses shut or opens the hosethrough-flow.
 24. A valve as set forth in claim 23, wherein the motor isa servomotor.
 25. A valve as set forth in claim 24, wherein the controlvalve is driven by a linear drive, wherein the linear drive is regulatedin dependence on the signal from the pressure sensor.